Semantic Web - Syllogisms, Global Ontologies and blue-eyed ideals

Shirky: The Semantic Web, Syllogism, and Worldview

Clay Shirky delivers the most concise, accurate and true criticism of the so-called Semantic Web. It's a very weel-argued criticism, derailing the whole idea of a global ontology, and pointing out that a universal system based on Syllogisms will fail at the really difficult part, namely dealing with uncertainties, generalisations and half-truths. The same uncertainties, generalisations and half-truths that humans base pretty much all our conversations and value-statements on. It's insightful for anyone who's been grasped by the 'sweetness' of the semantic web vision and confirming for anyone who's been a sceptic all along.

Oh, and interesting for anyone who's never given the sematic web a second thought (much like myself), because it deals with larger issues, i.e, the (un)likeliness of ever coming up with a global, machine-understandable ontology, and the general idea of solving the trivial problems, and ignoring the hard ones, that seems to be a favourite amongst techies everywhere (myself definitely included ;-)

Any attempt at a global ontology is doomed to fail, because meta-data describes a worldview. The designers of the Soviet library's cataloging system were making an assertion about the world when they made the first category of books "Works of the classical authors of Marxism-Leninism." Charles Dewey was making an assertion about the world when he lumped all books about non-Christian religions into a single category, listed last among books about religion. It is not possible to neatly map these two systems onto one another, or onto other classification schemes -- they describe different kinds of worlds.

Because meta-data describes a worldview, incompatibility is an inevitable by-product of vigorous argument. It would be relatively easy, for example, to encode a description of genes in XML, but it would be impossible to get a universal standard for such a description, because biologists are still arguing about what a gene actually is. There are several competing standards for describing genetic information, and the semantic divergence is an artifact of a real conversation among biologists. You can't get a standard til you have an agreement, and you can't force an agreement to exist where none actually does.